Association between Her2/neu status in colorectal carcinoma and clinicopathological features: a retrospective study using whole – tissue sections

The human epidermal growth factor receptor 2 (Her2/neu) signal pathway plays a significant role in the occurance of various solid tumor types. The rate of Her2/neu in colorectal carcinoma (CRC) is not clearly elucidated. In this study, we discuss the association between Her2/neu overexpression and clinicopathological parameters in CRC. Her2/neu immunohistochemical (IHC) staining was performed on whole sections of formalin fixed paraffin embedded tumor tissues of 100 CRC resections. Cases with score 3+ and score 2+ expressions were further evaluated by silver in-situ hybridization (ISH) for the existence of Her2/neu gene amplification. Her2/neu membranous overexpression was observed in 12 of the 100 cases (6 cases with a score 3+ and 6 cases with a score 2+) and 6 of these were heterogenous. There were 10 cases with Her2/neu amplification (6/6 score 3+, 4/6 score 2+). Strong cytoplasmic staining was observed in 5 cases. Membranous scores were either 3+ or 2+ in 3 of these 5 cases. Moreover, there was Her2/neu amplification in 2 of these 3 cases. Her2/neu amplification status and overexpression was not related to clinicopathological parameters and overall survival. More clear results can be obtained from studies with Her2/neu IHC and ISH test on whole sections.